Armrest support



FIG. 1 is a right side perspective view of an armrest support illustrating my design,

FIG. 2 is a left side perspective view thereof,

FIG. 3 is a top view thereof,

FIG. 4 is a bottom view thereof,

FIG. 5 is a left side view thereof,

FIG. 6 is a front view thereof; and,

FIG. 7 is a back view thereof.

The portions shown in broken line are not part of the design as claimed. 

The ornamental design for an armrest support, as shown and described. 